Oregon heath officials report in the Journal of Infectious Diseases that they traced an isolated outbreak of norovirus to a reusable grocery bag. The virus was passed among members of an Oregon girls’ soccer team in October 2010.

The Oregon soccer team was staying in a hotel in Seattle, where they had traveled for a weekend tournament. On Saturday, one girl developed stomach cramps, vomiting and diarrhea (it’s not clear how the teen got infected, but norovirus causes about 21 million cases of intestinal distress each year in the U.S.). She spent the night with a chaperone, using the bathroom continuously overnight. Unfortunately, the chaperone had placed the reusable grocery bag containing cookies and chips in her bathroom.

Health officials believe virus particles were spread within the bathroom and settled in the bag. When the bag was swabbed for microbes two weeks after the girl’s episode, researchers found the same virus that had sickened the student.

On Sunday, the team’s 13- and 14-year-old members passed the bag around eating snacks from it during lunch. On Monday, six other girls got sick.

“This is the first-ever reported case of transmitting this virus with an inanimate object, basically,” Kimberly Repp, an epidemiologist with the Washington County Department of Health and Human Services told WebMD.

In general, microbes like bacteria and viruses cannot survive for long on inanimate objects such as bathroom surfaces or grocery bags. Usually, norovirus is transmitted through direct human contact, but as the report highlights, it can survive long enough on surfaces to sicken those in close proximity to an infected person.

Experts say it takes only about a dozen or so copies of norovirus to cause illness, making it one of the more easily transmitted bugs that sickens people. Often transmitted in contaminated food, such as leafy greens, fruit and shellfish, norovirus can cause severe stomach distress, vomiting, nausea and diarrhea.

Norovirus, which is often referred to as the “cruise-ship virus,” is known for spreading quickly and causing outbreaks of illness on ships, day care centers, nursing homes and locker rooms.

The Oregon outbreak is a good reminder that reusable totes should be washed and disinfected regularly, especially if they’re used to transport foods — raw poultry, meat, eggs and produce, for instance — that can carry potentially disease-causing bacteria, including E. coli and salmonella.

The more often reusable grocery bags are used, the more they’re likely to maintain colonies of bugs that could cause serious illness. So wash your bags or, to be extra safe, keep raw foods out of them altogether; instead, use plastic or paper bags for risky foods, then dispose of the bags at home.

And, if this needs to be said at all, keep food out of the bathroom.

Alice Park is a writer at TIME. Find her on Twitter at @aliceparkny. You can also continue the discussion on TIME’s Facebook page and on Twitter at @TIME.